Bibcode
Crespo-Chacón, I.; Montes, D.; García-Alvarez, D.; Fernández-Figueroa, M. J.; López-Santiago, J.; Foing, B. H.
Referencia bibliográfica
Astronomy and Astrophysics, Volume 452, Issue 3, June IV 2006, pp.987-1000
Fecha de publicación:
6
2006
Revista
Número de citas
47
Número de citas referidas
43
Descripción
We report the results of a high temporal resolution spectroscopic
monitoring of the flare star AD Leo. During 4 nights,
more than 600 spectra were taken in the optical range using the Isaac
Newton Telescope (INT) and the Intermediate Dispersion Spectrograph
(IDS). We observed a large number of short and weak flares occurring
very frequently (flare activity > 0.71 h-1). This is
consistent with the very important role that flares can play in stellar
coronal heating. The detected flares are non white-light flares and,
although most solar flares are of this kind, very few such events have
been observed previously in stars. The behaviour of different
chromospheric lines (Balmer series from Hα to H{11}, Ca II H &
K, Na I D1 and D2, He I 4026 Å and He I D3) was studied in detail
for a total of 14 flares. We estimated the physical parameters of the
flaring plasma by using a procedure that assumes a simplified slab model
of flares. All the obtained physical parameters are consistent with
previously derived values for stellar flares, and the areas - less than
2.3% of the stellar surface - are comparable with the size inferred for
other solar and stellar flares. We studied the relationships between the
physical parameters and the area, duration, maximum flux and energy
released during the detected flares.